1. Field of the Invention
The present invention relates to the field of actuators for magnetic disks.
2. Statement of the Problem
The performance of magnetic disk drives is limited by, among other factors, actuator access time and actuator contention. Actuator access time is the time it takes an actuator carrying a read/write head to move to the proper track on the magnetic data storage disk. This is constrained by the acceleration of the actuator due in part to the magnitude of the mass of the actuator and to the friction between the actuator and its surrounding structure.
Actuator contention is dependent upon capability of the system to manipulate a particular actuator to access a particular random track. Presently, individual actuators are used to allow individual heads to be positioned relative to the disk tracks. This requires additional support and guidance structure for each individual actuator. The prior art devices typically used ball bearings which increase the mass of the actuators and present a problem with vibration transmitted through the system.
Frandsen U.S. Pat. No. 4,331,990, discloses a plurality of actuators, each with flat wire loops mounted on a planar carriage frame which, in turn, is mounted on roller bearings to reduce the mass and the inefficiencies of the voice coil motor system. This system still requires considerable spacing between the carriages. This increases the overall size, mass and friction of the system, as well as contributing to inefficiencies in the magnetic flux.
Watrous U.S. Pat. No. 4,506,307, discloses an actuator using air bearings on parts of eight of the surfaces of an X-shaped structure of the actuator to reduce the mass of the system. The air bearings must be supplied by an external blower.
There still presently exists a need for an actuator mechanism utilizing a friction free support system for the carriage actuators and having damping capabilities to restrain against vibration in the system.
3. Solution to the Problem
The present invention solves these and other problems by providing a high performance disk drive having a plurality of single arm actuators.
The present invention provides a low mass, low profile actuator having a high efficiency and extremely low friction.
The present invention provides a system where multiple actuators may easily be stacked at the normal disk spacing with as many carriages as desired.